Disable Gradle file system watching in CI

File system watching is primarily used for incremental builds so in CI
this only just adds unnecessary overhead and eats up inotify watches
which can cause some of our tests to fail when these limits are hit.

.ci/jobs.t/defaults.yml

@@ -56,8 +56,8 @@
             COMPOSE_HTTP_TIMEOUT=120
             JOB_BRANCH=%BRANCH%
             HOME=$JENKINS_HOME
-            GRADLEW=./gradlew --parallel --scan --build-cache -Dorg.elasticsearch.build.cache.url=https://gradle-enterprise.elastic.co/cache/
-            GRADLEW_BAT=./gradlew.bat --parallel --scan --build-cache -Dorg.elasticsearch.build.cache.url=https://gradle-enterprise.elastic.co/cache/
+            GRADLEW=./gradlew --parallel --scan --build-cache --no-watch-fs -Dorg.elasticsearch.build.cache.url=https://gradle-enterprise.elastic.co/cache/
+            GRADLEW_BAT=./gradlew.bat --parallel --scan --build-cache --no-watch-fs -Dorg.elasticsearch.build.cache.url=https://gradle-enterprise.elastic.co/cache/
     publishers:
 # Disable Junit publisher for now since it's causing OOME on our Jenkins instance
 #      - junit: